In 1978, Frank Barrett, a construction worker in Dawson City, a town in the northern Yukon, was excavating the site of a new recreation center when he discovered reels of film poking out from the hard-packed terrain. He recognized the potential significance of the find and made official inquiries that ultimately led to careful digs to unearth the full complement of material, which turned out to be more than five hundred reels of highly flammable nitrate film. As it turned out, those reels, from the nineteen-tens and twenties, contained many fiction films (including ones by D. W. Griffith, Lois Weber, Allan Dwan, Tod Browning, and other early cinema luminaries) that hadn’t otherwise survived, as well as newsreel footage from the same period.

That’s where the filmmaker Bill Morrison comes in. In his new film, “Dawson City: Frozen Time,” currently playing in New York and expanding to other cities this Friday, Morrison looks at the surviving films and reconstructs the extraordinary arcs of political and cultural history that are latent in them. Since the footage was found in Dawson City, Morrison reconstructs the history of Dawson City as well, its cinematic history in particular, and discovers that the currents emanating from the found footage have strange doubles in the history of Dawson City itself, which, despite its isolation and obscurity, turns out—in his passionately discerning view—to be a hidden mainspring of modernity.

Morrison launches the story locally, with an American man’s discovery of gold along the Klondike River, in 1896. Word got out, a claim was staked for a town, the Mounties displaced the indigenous Hän people to make way for mining, and boatloads of prospectors arrived from San Francisco and Seattle. By 1897, the gold rush was in full swing, along with its snares and hazards. Morrison emphasizes that, of the hundred thousand travellers who sought their fortune in the Klondike region, seventy thousand either died en route or returned home—and he uses a comedic image from Charlie Chaplin’s 1925 masterwork “The Gold Rush” to illustrate the trip’s terrors.

Relying on footage from the Dawson City find, as well as from other archival sources, Morrison constructs a vibrant and alluring visual history. He respects the silence of the silent-film footage and adds no voice-over; his copious and trenchant commentary appears on the screen as titles superimposed on the footage, and the only voices in the film come from a few brief clips that feature recorded sound as well as brief but informative and hearty interviews with two archivists, Michael Gates and Kathy Jones-Gates, who played crucial roles in rescuing the Dawson City footage and ended up marrying each other. (Unfortunately, the overly insistent music, by Alex Somers, obscures the silence instead of enhancing it.)

The film locates extraordinary political and cultural tributaries, marked by archival footage, that arise from the history of Dawson City and the gold rush. For instance, Morrison notes that Donald Trump’s grandfather Fred Trump launched his real-estate empire with a brothel-cum-restaurant in the neighboring gold-rush town of Whitehorse (and includes a still image of the establishment). Dawson City was a rowdy home for transient prospectors; it thrived on gambling, grifting, and prostitution. But, as the gold rush quickly settled to a trickle, permanent residents purged the town of louche entertainments, which were quickly replaced by the new medium of movies, which proved extremely popular.

That hunger for entertainment, and for the new medium, accounts for the extraordinary diversity of the material in the Dawson City rediscoveries—not just dramas but newsreels, travelogues, and even scientific and ethnographic films turn up among the recovered reels. Morrison tells the strange story of how the reels ended up there. The remote region didn’t get films until years after their release; as a result, distributors didn’t want to pay for the return of those films, which had exhausted their commercial life. Dawson City exhibitors sought to store the films, but the highly flammable nitrate reels occasionally combusted spontaneously (Morrison documents the horrific and deadly history of film-centered fires, with their victims among the viewing public, as well as their ravages of studios belonging to Thomas Edison and Alice Guy-Blaché). As a result, many films were dumped in the river, others were burned in a huge bonfire, and those that remained were buried deep below the surface of the earth in a permafrost pit.

One newsboy in Dawson City in the late nineteenth century, Sid Grauman, got his first taste of movies there; he later move to Hollywood, where he founded, among other movie palaces, Grauman’s Chinese Theatre. A Dawson City bartender, Alex Pantages, joined with the entertainer “Klondike Kate” Rockwell to open a movie theatre, and he eventually became the head of one of the largest American movie-theatre chains. Jack London, of course, headed north in the gold rush, and stayed only briefly, but launched his literary career. The New York Rangers and Madison Square Garden have historical roots in gold-rush entertainments; even the form of this documentary itself, with its use of archival photographs, has its roots in a 1957 documentary, “City of Gold,” based on rediscovered archival Dawson City gold-rush images by Eric Hegg.

But the core of the film, and the supreme display of the intellectual depth of Morrison’s film-editing virtuosity, involves baseball and politics. It’s too good a story to spoil in detail; Morrison sets it up with a wry wink, showing himself on a TV sports broadcast, introducing footage of the 1917 and 1919 World Series, which he found among the Dawson City reels. The 1919 Series, of course, is the one that’s infamous for the “Black Sox” scandal, when players for the Chicago White Sox were found to have thrown games for the benefit of gamblers, and Morrison centers the tale on that scandal—and on the images from a game that he analyzes in slow motion to show how the game-throwing worked. But, more important, he also links that seemingly isolated event to the wider politics of the time, as documented in newsreel footage also discovered in the soil of Dawson City. It’s a tale that involves the incipient union movement and the collusion of government and business to repress it. It encompasses the First World War, the Red Scare, protests in New York, and the deportation of “undesirable” immigrants; and it’s centered on Judge Kenesaw Mountain Landis, a rigid conservative who, in the wake of the Black Sox scandal, was appointed the first commissioner of Major League Baseball. Along the way, Landis kept the game socially and politically regressive for decades. (Morrison’s ingenious use of slow motion to analyze the World Series footage film suggests what’s lacking from the rest of the film: similarly interventionist editing, whether slow motion or freeze-frames, zoom-ins or iris-ins, to emphasize and prolong beautiful expressions, gestures, and moods from the found footage.)

Most of the Dawson City rediscoveries that Morrison deploys have been damaged by their time in the ground. Rather than restoring the footage, or trying to elide or correct the damage, Morrison revels in it, maintaining it onscreen in a way that’s consistent with, and that reflects, his prior practice in his best-known film to date, “Decasia,” from 2002. In “Decasia,” Morrison collects archival footage that was damaged or had deteriorated, and his assemblage of it proves that the physical degradation of the images, far from rendering them unusable and unshowable, adds several other layers of expression to them. He showed that the visual patterns of the image decay are beautiful in themselves, as a kind of found visual poetry of textures and shapes, and that the deterioration of the images is an overriding metaphor in itself, one that reinforces the fragmentary yet miraculous recuperation of lost time.

“Decasia” is an experimental film in the most literal sense, and the fruits of that experiment are reflected in “Dawson City,” where most of the rediscovered footage is mottled, decayed, ravaged—and that menacing ruin is part of their power. Here, it suggests death in motion, evoking images that time has rendered cadaverous and— despite the embalming process of film-processing chemistry—helpless against decomposition. That decay makes these images look like the undead who return from the void to bear silent witness to vanished and voiceless lives. In “Dawson City,” Morrison offers a fiercely precise and discerning look at movies themselves as embodiments of history. In the process, he retunes our relationship with the ubiquitous cinematic archive—with the fresh batch of images that get delivered through the electronic pipeline by the minute—and with the very question of what’s contained, or what’s hidden, in the seemingly smooth and seamless flow of a movie.